The answer 56 it’s already put in simplest form
To find an average you add all numbers together then divide by the amount of numbers that you added. So if there are 4 numbers you would divide by 4. By going backwards you can find the answer. Multiply 5 by 4 and you get 20, which is the answer.
Go 0.35•22 and you get 7.7
Looks like the series is supposed to be
The series telescopes; consider the 
th partial sum of the series,
As 
, the second term converges to 0, leaving us with
A. -6/7
Because:
(2,6) (8,-1)
(x1,y1) (x2,y2)
x1 = 2. Y1=6. X2=8. Y2= -1.
Equation for slope is m = y2-y1
x2-x1
-1-6 = -7
8-2=6
